Terminology on topics related to;
nuts and bolts,
threaded fasteners and tightening techniques
POOCHING
Pooching is a term sometimes used to describe the effect of the area
immediately surrounding a tapped hole being raised up as a result of
the tension from the stud. Tapped holes are often bored out for the
first couple of threads to eliminate this problem.
PRELOAD
The tension created in a fastener when first tightened. Reduces
after a period of time due to embedding and other factors.
PREVAILING TORQUE
The torque required to run a nut down a thread on certain types of
nuts designed to resist vibration loosening. The resistance can be
provided by a plastic insert or a noncircular head.
PROOF LOAD
The proof load of a nut is the axially applied load the nut must
withstand without thread stripping or rupture. The proof load of a
bolt, screw or stud is the specified load the product must withstand
without permanent set.PRYING
The amplification of an external force acting on a bolt by a lever
action which can occur when that force is an eccentric tensile load.
REDUCED SHANK BOLT
A bolt whose shank diameter is smaller than the nominal diameter of
the bolt (normally the shank diameter of such a bolt is
approximately equal to the effective diameter of the thread).
PILES
Term used in structural engineering for the joint plates.
PITCH
The nominal distance between two adjacent thread roots
PLY
A single thickness of steel forming part of a structural
joint. |
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